This invention relates generally to the fields of molecular physics and material detection, and more specifically on the physical concept of molecular rotational frequencies in order to detect the presence of specific molecules of interest.
Current material detection solutions rely either upon what is known as “sniffers” or on optically-based technologies. Sniffers are systems that can detect the presence of specific materials. This is done by using a cantilever sensor (usually a MEMS cantilever) with a tip which only reacts to a specific type of material. An example of a sniffer is the gate at airports where an air current is blown at the person standing within the gate. Molecules dislodged as a result of the air current are blown through an air conductor with a cantilever inside of it. As stated, the cantilever only reacts to a specific type of material. Once a molecule (or molecules) of the material touch the tip of the cantilever they change the resonance frequency of that cantilever. The difference between the original resonance frequency and the current resonance frequency allows one to “know” that the specific material has been detected and to act upon this knowledge.
Sniffer systems suffer from the following disadvantages:                Accuracy of detection—the ability of the system to detect the presence of a material is highly dependent upon its concentration in the sampled area. Since such a system relies upon the existence of residual amounts of the illicit material; the farther it is from the source the less accurate it is.        Limited in types of materials it can detect—the system relies upon the concept of the cantilever sensor, where the tip is treated to react to a specific material. This limits the range of materials that can be recognized.        
Optical systems rely upon the “rotational frequency” effect in molecules. A beam of light at a specific wavelength (frequency) is transmitted to a specific target area. When the light at that specific wavelength excites the material of interest, the reflected light will be at a different wavelength (usually double that of the original transmitted wavelength). By knowing when the original light was transmitted and knowing that only this transmission is what has caused the detection of a new wavelength, one can ascertain that the material of interest is present. An example of the way this system is used is when a swab is passed over baggage and inserted in a sealed box. Within this box the light at a specific wavelength is directed at the sample and the existence of illicit materials is thus confirmed if a specific shift in wavelength is detected.
The main limitations of the systems that rely upon the “rotational frequency” effect are that they require some sort of physical contact with the sample. An additional drawback is that the amount of energy required to correctly trigger the “rotational frequency” effect must be quite precise; using too little or too much energy will not provide the necessary result for the analysis.
It is therefore a first object of the present invention to provide an improved means for spectral analysis of unknown materials that overcomes the aforementioned and other disadvantages of the prior art.
Embodiments of the present invention alleviating some of these disadvantages will now be described. Embodiments of the present invention can use a terahertz (THz) signal generator for the analysis of molecules in a sample. The analysis can use a chamber that can be made very small relative to current systems, however, it should be clear to a person skilled in the art that the chamber can be made whatever size suits the needs of the specific application. The present system does not require any physical contact with the molecules it analyzes, and can detect minute concentrations of a material of interest.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of illustrated embodiments.